Are Serum Immunoglobulins A Predictive Biomarker Of Response For Anti-Il5 Therapies?

Approval of biologics has recently revolutionized the management of severe asthma. However, predictive biomarkers remain highly needed to improve the patients’ selection. This study aims to determine if serum immunoglobulins (Ig) may be predictive biomarkers of response for anti- interleukin 5 (IL5) therapies. Inclusion criteria were: patients with severe asthma being treated with anti-IL5 therapies, Ig and IgG subclasses quantification before treatment and at 6-month. The treatment response was evaluated by the GETE score (Global Evaluation of Treatment Effectiveness) at 6 months. A total of 50 patients were included. Median age was 56 [IQR 48.8-65.3] and 50% were females. Compared to baseline, a significant increase in IgG was observed at 6 months (9.2 [7.8-10.2] g/l vs 10.1 [8.8-11.1] g/l, p=0.04). A non-significant decrease in serum IgG4 was also observed at 6 months (0.68 [0.36-1.13] g/l vs 0.50 [0.33-0.72] g/l, p=0.09). The area under the ROC curve for the prediction of the treatment response was 0.58 [95%IC 0.40-0.77] for blood eosinophil count (p=0.37), 0.75 [95%IC: 0.58-0.92] for serum IgG concentration (p=0.009) and 0.66 [95%IC: 0.49-0.82] for serum IgG4 concentration (p=0.09) (Figure 1). According to Youden index, serum IgG concentration ≥ 9.2 g/l predicts the response to anti-IL5 therapies with a sensitivity of 76.9% and a specificity of 75.7%. Conclusion: Baseline serum IgG concentration may be a useful tool to predict the anti-IL5 therapies response.